The corn wet milling process generally starts with dry or wet (fresh) corn kernels that have been inspected and cleaned to remove cobs, chaff, and other debris. This cleaned corn is typically filled into a battery of large steeping tanks or steeps, where the corn is soaked in hot water. Each steep is generally equipped with piping to move steep water from one steep to another, to pass it through a heat exchanger, and/or to withdraw it from the system. The steeping is generally carried out in a continuous countercurrent process, i.e., the flow of water is countercurrent to the flow or movement of corn in the steeps. Small amounts of sulfur dioxide have been conventionally added to the process or steep water at the beginning of the countercurrent process. Over time, the corn swells from absorbing the sulfur dioxide water, which, in combination with mild acid conditions, helps to soften the corn so as to optimize separation of corn components.
A proper soaking or steeping is essential for desirable corn component yields and quality. Steeping, however, is more than simple water soaking of corn. It generally involves complex and interrelated variables, including maintaining a correct balance of water flow, temperature, sulfur dioxide concentration, and an adequate population of lactic acid bacteria, for example. Also, the steeping process, which can last up to 50 hours or more, is typically the slowest part of the corn wet milling process. Because of that, a reduction in overall steeping time can realize significant cost savings at least in terms of decreased energy consumption and can generate additional revenue in terms of increased output. While wet mill operations are continually looking for ways to reduce overall steeping time, they are also generally looking for ways to increase component yields, e.g., starch yields, while maintaining desirable quality.
It would thus be beneficial to provide an improved process for steeping corn in a corn wet milling process and a steeping system therefore, which can increase component yields, such as starch yields, for example, while maintaining desirable quality and which may decrease the overall steeping time.